Zigzag stitch attachment for needle equipped sewing machines



ZIGZAG STITCH ATTACHMENT FOR NEEDLE EQUIPPED SEWING MACHINES Filed Dec. 18, 1957 '3 Sheets-Sheet 1 INVENTOR emu H. NJRKER ar%W% I June 28, 1960 c, U R 2,942,563

ZIGZAG STITCH ATTACHMENT FOR NEEDLE EQUIPPED SEWING MACHINES Filed Dec. 18, 1957 3 Sheets-Sheet H6. 14- 53 /-'/6. I6 W i 4 $7 (4" .57 57 63 63 56 wmg lx 64 2 55 INVENTOR cal-1 1/. WU'RAER June 28, 1960 c H. WORKER ZIGZAG STITCH ATTACHMENT FOR NEEDLE EQUIPPED SEWING MACHINES Filed D80. 18, 1957 3 Sheets-Sheet 3 ZIGZAG STITCH ATTACHMENT FOR NEEDLE I EQUIPPED SEWING MACHINES Carl H. Wiirker, Wagenweg 198, Aistaig am Neckar,

- Germany 7 Filed Dec. 18, 1957, Ser. No. 703,692 Claims priority, application Germany Mar. 23, 1957 14 Claims. (Cl. 112160) This invention relates to sewing machine attachments which make possible zig-zag stitch and Ornamental stitch work, and in particular buttonhole work, on conventional sewing machines equipped'with a needle bar movable only in a vertical direction.

Such attachments are provided generally with a clothor fabric-displacing lever which is actuated either directly or indirectly by means of a drive mechanism actuated in turn by the needle bar of the sewing machine, the displacing lever being moved to and fro in an approximately horizontal plane so as to impart to the material or fabric gripped thereby a similar to and fro motion in a direc-' tion substantially transverse to the feed direction of the sewing machine.

In most attachments of type, the fabric-displacing lever is actuated directly by means of a. rotating control cam. *It'has, however, been already proposedto actuate the displacing lever indirectly with the aid of an intermediate connecting lever which is directly actuated by the aforesaid control cam. In either case, the arcuate length of the path of throw. or deflection of that end of the displacing lever which carries the fabric-displacing foot determines the width of the zigzag stitches, i.e., the length of thread from one stitch apex to the next.

Such stitch width, of course, varies in size depending on the work to be done. Especially for buttonhole work, the stitch widths are small during forming of the buttonhole side borders and large during forming of the opposite end borders of the buttonhole. It has, consequently, been customary in known attachments. of this type to mount the axis of rotation-defining pivot pin of that lever which determines the throw of the fabric displacing foot, on a carrier which is guided on the drive housing of the attachment for displacement longitudinally of'the' displacing lever. Thus it is possible to enlarge or decrease the length of the lever arm determining the dis-' hole side borders. By means of this guiding of the buttonhole side borders, it becomes possible to form these borders completely parallel to and at a constant distance from oneanother without any need for the operator of the sewing machine to be possessed of any special skill or to exercise any great care.

It has, however,..be'en1found that precisely due to the secure. guiding of. they buttonhole side borders, the transverse end borders of. the buttonhole, which must be formed with a relatively large stitch width, are not sym-' metrical to the center line of the button hole but rather are symmetrical to the center line of one of the two buttonhole side borders. These end borders are thus laterally shifted relative to the buttonhole center line.

- =For-the purpose of avoiding this disadvantage it has already been proposed to construct the pivot pin for the' actuating lever of the cloth-displacing foot as an eccentric which is rotatably journaled in an' adjusting slider arranged for longitudinal displacement relative to the actuating lever, the eccentric being rigidly connected with a' lever-like carrier by means of which it can be swung or oscillated about its axis of rotation. During such swingihg movement of the eccentric, the cloth-displacing lever, or the-actuatingnlever'thereof, can be swung in such, a manner that a lateral displacement of the stitching region takes place. Thus, when forming a button hole and after completing one of the buttonhole side borders, it, is possible to adjust the eccentric by shifting the adjusting slider'to a larger stitch width position and then to rotate the eccentric by means of the lever-like carrier thereof in such a manner that the displacing lever deflections are symmetrical with respect to the center line of the buttonhole. J Althoughthe buttonhole end stitches formed by such an attachment no longer'are symmetrical with respect to the center line of one of the buttonhole side borders;

this type of attachment sutfers from the disadvantage that the operator must perform two separate adjusting movements; 'First he must shift the eccentric longitu dinally of the displacing'lever through the intermediary of the purely rectilinearly movable adjusting slider, and

placing foot throw by shifting the pivot-of the said lever.

In attachments with a direct drive or actuation of the fabric-displacing lever, the arm of the displacing-lever. at which the displacing foot is carried determines the throw or deflection of the latter, while in attachments with indirect actuation of the displacing lever by means of an intermediate lever, the magnitude of thethrow depends on the length of that arm lever engaging the fabric-displacing lever.

For doing buttonhole work it is advantageous to emof the intermediate ploy a specially constructed displacing foot, i.e., one

then be must rotate the eccentric by means of the leverlike carrier. 7 7

It is, therefore, an important object of the present invention to provide means facilitating precise sewing 'of buttonhole borders so as to ensure that the end portions the buttonhole center line. 1

Another object of the present invention is the provi-' sion of means contributing .to rapid and facile buttonhole sewing with the aid of a mechanism imparting to the cloth-displacing means of a zig-zag stitch sewing machine attachment all-the requisite movements for automatically controlling both the widths and positions of the various stitches. r p I A'fiurther object of the-present invention is the provi'- sion of meansdesigne'd to. avoid the hereinabove st'ate'd disadvantages and drawbacks of known zig-zag stitch at-' tachments. To this end, means are provided which im part to the carrier of the eccentric, during displacement of said carrier in a longitudinal direction, a swinging movement about the axis of a guide bolt or extension of the eccentric and thus effect a rotation of the eccentric bolt in order to shift the stitching region laterally.

of'said borders are disposed symmetrically with respect to Thisobject may be implemented'in a number of con- I I structional forms. By way of example, the carrier ofthe eccentric can be linked to a substantially purely rectilinearly displaceable adjusting slider and have its swinging movements positively efiected by a control cam. Alter natively, it is also possible to employ'the adjusting slider itself as the'eccentric carrier" and tobring about its swing- Patented June 28, 1960' ing movements by means of a slot provided therein or by means of a link or lever articulated thereto.

With any of these constructions, the operator is required to carry out only a single adjusting motion in order to bring about a stitch-enlarging or decreasing longitudinal displacement' of the eccentric and at the same time a rotation thereof for laterally displacing the stitching region.

The foregoing and other objects and advantages of the present invention will be more fully understood from the following detailed description when read in conjunction with the accompanyingdrawings, in which:

Fig. 1 is a partly sectional side elevational view of a sewing machine attachment constructed in accordance with the present invention, the housing being partly broken away;

Fig. 2 is a bottom plan view of the attachment in .position for sewing a buttonhole side border;

Fig. 3 is a bottom plan view of the attachment in position for sewing a transverse end border of the buttonole;

Fig. 4 is a plan view of the eccentric and its carrier;

Fig. 5 is a sectional view taken along the line V-V in Fig. 4;

Fig. 6 is a sectional view, similar to Fig. 5, of a modi fied form of eccentric and carrier construction, the section being taken at right angles to the plane of Fig. 5;

Fig. 7 is a bottom plan view of still another modified construction of the eccentric and its carrier;

Fig. 8 is a sectional view taken along the line VIII- VIII in Fig. 7;

Figs. 9 to 12 are schematic plan views of four different modifications of the construction of the eccentric-displacing means according to the present invention;

Fig. 13 is a schematic illustration, on an enlarged scale,

of the position of the cloth-displacing lever subsequent to the sewing of the first buttonhole side border;

Fig. 14 is a vertical transverse sectional view of the cloth-displacing foot of the attachment and the clothsupporting plate of the sewing machine, these parts being positioned relative to one another in the same manner as shown in Fig. 13; and

Figs. 15 and 16 are schematic views similar to Figs. 13 and 14, respectively, but illustrating the cloth-displacing foot in the position symmetrical with respect to the buttonhole center line which it assumes according to the invention when sewing a buttonhole end border.

Referring now more particularly to Figs. 1 to 3, the attachment there shown comprises a drive housing consisting essentially of a floor or bottom plate 20 and two vertical side walls 21 attached thereto and. thus forming a frame of substantially U-shaped cross-section. "The drive housing 20-21 is covered and closed from the exterior surroundings by means of a strip of metal 22 and is fixed to the presser bar 24 of a sewing machine (indicated only partly and in phantom outline) by means of a clamp dog 23. Rotatably journaled between the side walls 21 of the drive housing is a control or cam drum 25 the shaft of which carries a ratchet 30 having teeth engageable by a spring-biased pawl 29 linked or pivotally mounted on a control lever 28 articulated at 26. to the needle bar 27 of the sewing machine, whereby upon vertical reciprocation of the needle bar the control drum 25 is rotated intermittently in a clockwise direction.

The cam drum 25 is provided in known manner with a wave-shaped peripheral control or cam: groove into which extends a runner or follower in the form of a small roller 31 rotatably mounted on a follower pin 32. The pin 32 extends through a transverse slot in the bottom plate 20 of the drive housing and is fixedly connected to the rear (right-hand) end of a cloth-displacing lever 33, as by being riveted thereto.

The cloth-displacing lever 33 lies against the bottom side of the housing bottom plate 20 and carries at its front (left-hand) end a bearing fork 34 in which a clothdisplacing foot 35 is pivotally supported by means of a transverse pin or axle 36. The displacing lever and foot jointly constitute cloth-displacing means.

A cylindrical part or main body portion 37 of an eccentric bolt constitutes the pivot means for the cloth-displacing lever 33, the eccentric bolt having an upper cylindrical extension 38 which is guided for longitudinal sliding movement in an elongated slot 39 formed in the housing bottom plate 20, a cross bar 40(see also Fig. 5) connected to the upper end of this extension and extending across this slot ensuring that the guide extension 38 cannot be released from the housing bottom plate. The eccentric body portion 37 is disposed within the confines of an elongated, longitudinal slot 41 provided in the clothdisplacing lever. An extension 42 of the eccentric bolt provided below the eccentric body portion 37 and arranged coaxially with the upper extension 38 extends through the front (left-hand) end of an adjusting slider 43 and is fixedly connected by means of a rectangular portion 44 and a rivet head 45 to the front (left-hand) end of a link 46. The latter thus constitutes a carrier for the eccentric.

The adjusting slider 43 is articulated at its rear (righthand) end by means of a link pin 47 with one arm of a two-armed adjusting lever 48 swingably mounted on a pivot pin 49 fixed to the housing bottom plate 20 (see Figs. 2 and 3). Thepivot pin 49 extends through the rear (right-hand) end of the adjusting slider 43 which is for this purpose provided with an arcuate slot 50 concentric with the link pin 47. Thus it will be seen that by swinging the adjusting lever 48 about the axis of its pivot means 49, the adjusting slider 43 and the eccentric 37 coupled to the latter by means of the lower extension 42 can be displaced either frontwardly (to the left) or rearwardly (to the right) the front end of the adjusting slider 43 being constrained to rectilinear motion by means of the guide pin or upper extension 38 of the eccentric 37 sliding in the slot 39 of the bottom plate 20. Inasmuch as the eccentric 37 is rigidly connected by means of its rectangular portion 44 to the link or carrier 46, the latter is forced to partake of the longitudinal motion of the adjusting slider 43.

In the rear end of the link 46 is provided a cam slot 51 extending obliquely to the guide slot 39, and through the slot 51 extends the lower portion of the pivot pin 49 in the manner of a guide bolt, the pivot pin 49 being provided with a head 52. When the side edges of the oblique cam slot 51 slide past the pivot pin 49 during a longitudinal displacement of the link 46, the latter is simultaneously forced to execute a swinging movement, as a result of which the eccentric 37 rigidly connected with the link is rotated. Consequently, the eccentric 37 engaging in the slot 41 of the cloth-displacing lever 33 simultaneously effects the desired lateral shifting of the latter so that the stitching region of the sewing needle 53 (shown in phantom outline in Fig. l) is correspondingly laterally displaced, as may be clearly seen from Figs. 2, 3 and 13 to 16.

Referring specifically to these last mentioned figures, it will be seen that the clothor fabric-displacing foot 35 is provided with a wide needle or sewing aperture 54- ex tending transversely to the direction of sewing and so dimentioned as to leave unblocked the needle aperature 55 in the cloth supporting plate 56 of the sewing machine in all positions of the cloth-displacing foot 35.

On its lower surface the foot 35 is provided with conventional teeth 57 as well as with two guide grooves-58 and 59. The groove 58, when viewed in the direction of sewing, lies in front of the needle aperture 54 and is only wide enough to accommodate and guide a single buttonhole side border. The second groove 59 is arranged behind the needle aperture 54 and is suflieiently wide to accommodate both side borders of a buttonhole simultaneously.

As seen in the direction of sewing, the left-hand side edge. of the rear groove 59 constitutes a rectilinear extenestates 3 sion of the left-hand side edge of the front groove 58. A further groove 60 is provided in the bottom surface of the foot 35 adjacent and to the right of the front groove 58, the groove 60 being provided with an upwardly leading aperture 61 through which a gimp or like fancy, ornamental thread may be introduced. During sewing of a buttonhole side and when the cloth-displacing foot 35 is in its center position, this groove when viewed in the direction of sewing is disposed with its center beneath the sewing machine needle 53 and defines the center line of the buttonhole side border to be formed (see Fig. 13).

In operation, the operator first sews a buttonhole side border 62 with a relatively narrow stitch width, during which time the attachment is adjusted to the position shown in Fig. 2. Thereafter, the cloth-displacing foot 35 is lifted from the cloth, fabric or like material 63 by lifting of the presser bar 24, and the cloth while still penetrated by the needle 53 is then rotated through an angle of 180, so that the finished first buttonhole side border 62 is caused to lie in the front guide groove 58 of the displacing foot 35. The needle 53 is now'raised and the attachment adjusted through appropriate manipulation of the adjusting lever 48 to a larger stitch width (the position shown in Fig. 3), and the first buttonhole end border 65 is then sewed, if desired while the cloth-feeding means 64 of the sewing machine are rendered. inoperative. Thereafter, the attachment is again adjusted to the smaller stitch width condition and the second buttonhole side border 66 sewed, during which time the first buttonhole side border 62 lying in the groove 58 guides the cloth 63 in a straight line to insure that the second buttonhole side border 66 is formed exactly parallel to the side border 62 and at a constant distance therefrom (see Figs. 13 and 15). Finally, the attachment is again adjusted to the wide stitch condition and the second buttonhole end border 67 sewed.

When known zig-zag stitch attachments without displacement or shifting of the stitching region are employed, the cloth-displacing foot 35 is always retained in its initially adjusted position regardless of whether narrow or wide stitches are used. Accordingly, whenever it was required to sew a buttonhole end border 65 or 67 with one of such known attachments in the manner described above, it was found that such end border lay symmetrical with respect to the buttonhole side border 66 and not symmetrical with respect to the center line of the buttonhole. The end border of the buttonhole thus would extend beyond and to the right of the second buttonhole border 66.

Rotation of the eccentric 37 now leads to the sought and highly advantageous result that, upon adjustment of the attachment to its wide stitch condition (Fig. 3), the displacing foot 35 and the material 63 are displaced so far to the right that the buttonhole end borders 65 and 67 are automatically positioned symmetrically with respect to the center line of the buttonhole (see Fig. 15). The displacing lever 33, for this purpose, is swung to the right about its pivot axis 32 together with the material 63 by means of the eccentric 37, in such a manner that in the center position of the displacing lever 33 the center line of the buttonhole lies beneath the needle 53 (see Figs. 15 and 16).

It is this feature of the present invention which enables the zig-zag deflections of the displacing foot 35 to be exactly symmetrical with respect to the center line of the buttonhole.

The construction of the eccentric and its carrier described with relation to Figs. 1 to can be modified as shown in Figs. 6- to 8. By way of example, it is possible to mount on, i.e., about, the eccentric 37 a rectangular slide block 68 (Fig. 6) rotatable about the eccentric and slidably riding in the slot 41 of the cloth-displacing lever 33 in lieu of the eccentric 37, thereby additionally preventing premature wear and deterioration of the eccentric due to its constant rubbing against the edges of the .46 constituting the carrier for the eccentric 37 is provided with a transverse slot 69 which is longer than the rectangular portion 44 of the eccentric belt, so that the latter can be laterally displaced along the slot 69 in order to adjust the angle of rotation of the eccentric 37 and to compensate for manufacturing tolerances.

In this case, the eccentricbolt is provided below the rectangular portion 44 with a threaded extension 70 about which is mounted a washer 71 bridging the slot 69, a nut 72 being screwed onto the extension 70 in order to clamp the link 46 between the washer 71 and the lower extension 42 of the eccentric bolt.

Turning now to Figs. 9 to 12, several further modifications of the present invention are there schematically illustrated, all of those structural elements identical with elemens shown in Figs. 1 to 3 being designated by the same reference numerals.

In Fig. 9, the slider 43 shown in Figs 1 and 3 has been omitted in order to simplify the construction. Instead of that, the carrier 946 of the eccentric 37 is directly articulated to the adjusting lever 948 at 947. The adjusting lever 948 is provided with an elongated slot 973 through which extends a pivot pin 949 fixed to the drive housing bottom plate 20, so that the adjusting lever 948 when swinging about the axis of the pivot pin 949 is longitu-' dinally displacedl This is necessary because the carrier 946 when being displaced longitudinally carries out at the same time a swinging movement about the upper guidev pin or extension 38 of the eccentric 37.

The carrier 946 is forced to execute this swinging movement by an oblique cam slot 951 which is provided therein in a manner corresponding to the slot 51 in the link 46 shown in Figs. 1 to 4 and which surrounds the pivot pin 949. If the adjusting lever 948 is pivoted in a clockwise direction about its pivot axis 949, the eccentric carrier 946 is shifted to the right to adjust the attachment for wide stitches and is simultaneously forced to execute a clockwise swinging movement so that it is displaced downwardly with reference to the plane of the drawing, with the adjusting lever 948 linked thereto. The swinging of the eccentric carrier 946 concurrently effects a swinging of the eccentric 37 rigidly connected thereto and, as a consequence thereof, the hereinabove described swinging of the cloth-displacing lever 33 and corresponding lateral displacement of the stitching region of the needle 53. Upon counterclockwise swinging of the adjust-ing lever 948, the eccentric carrier 946 is displaced to the left to adjust the attachment for narrow stitches, and is simultaneously swung counterclockwise together with the eccentric 37. I

According to the embodiment of the invention shown in Fig. 10, the slider 43 shown in Figs. 2 and 3 has been omitted in order to simplify the construction. Instead of that, the adjusting lever 1048, like the lever 48 in Figs.

1 to 3, is mounted for swinging movement on a pivot pin 1049 fixed to the housing-bottom plate 20. In contra distinction to the first embodiment, however, the adjusting lever 1048 is provided with an elongated slot 1074 for accommodating a link pin 1047 by means of which the lever 1048 is articulated to the eccentric carrier 1046.

This is required because the latter is forced by means of an oblique cam slot -1 provided therein and surrounding the pivot pin 1049 to execute during each longitudinal displacement a concurrent swinging movement about the upper guide extension 38 of the eccentric 37 slidably accommodated in the slot 39 of the housing bottom plate 20.

The operation of this embodiment of the invention is the; same as that of the embodiment of Fig. 9 and thus need not be further described in detail. I

In the embodiment of Fig. 11, the eccentric 37is liked to a carrier 1146 provided with .an oblique cam slot- 1- 7 surrounding the pivot pin 11.49 of the adjusting lever 1148, the slot 1151 imparting to the carrier 1146 during each longitudinal. displacement a concurrent swinging move- ;n7ent aboutthe upper guide extension 38 of the eccentric The adjusting slider 43 shown in Figs. 1 to 3 is, in this embodiment, replaced by a simple coupling element 1143 which is linked at its left-hand end with the lower extension 42 of the eccentric 37 and at its right-hand end by means of a link bolt 1147 with the free end of the adjusting lever 1148. The operation of this embodiment is the same as that of the embodiment of Figs. 1 to 3 and thus requires no further explanation.

The embodiment of Fig. 12 differs from the foregoing in that the eccentric 37 is connected with the front (lef-thand) end of a coupling element 1246 which thus also constitutes the carrier for the eccentric. The rear (righthand) end of the carrier 1246 is linked to the free end of the adjusting lever 1248 by means of a link pin 1247. As in the other embodiments of the invention, the adjusting lever 1248 is swingably mounted on a pivot pin 1249 affixed to the bottom plate 20 of the housing. When the adjusting lever 1248 is swung in the direction of the arrow, i.e., counterclockwise, the eccentric carrier 124 6 is displaced to the left, at which time the upper guide extension 38 of the eccentric 37 is linearly displaced in the slot 39 of the bottom plate 29.

As a consequence thereof, the eccentric carrier 1246 during its longitudinal displacement carries out, in the manner of a connecting rod of a crank drive, an additional clockwise swinging movement about the axis of the extension 38 of the eccentric 37. The consequently initiated rotation of the eccentric 37 effects, as in all of the previously described embodiments of the invention, a corresponding displacement or shifting of the stitching region of the needle 53.

t The modifications illustrated in Figs. 6 to 8, i.e., guiding of the eccentric by means of the slide block 68 and the releasable and adjustable connecting of the eccentric 37 to its carrier, may equally well be employed in the embodiments of Figs. 9 to 12.

In the claims appended hereto, that part of the attachment to which the eccentric 37 is afiixed is generally referred to by such terms as carrier means or carrier for the eccentric" or eccentric carrier or the like, and it is one of the pincipal features of the invention that this carrier is guided in such a manner that during each longitudinal movement there is imparted thereto a concurrent swinging movement which effects a rotation of the eccentric 37 about its guide extension 38.

The oblique cam slot 51 (951, 1051, 1151) in the eccentric carrier consists, in the illustrated embodiments of the invention, of a straight center portion and two contiguous oppositely curved arcuate end portions 51 and 51 (Fig. 4) oriented essentially longitudinally of the carrier. The purpose of these end portions 51 and 51" is to ensure that a rotation of' the eccentric 37 takes place only within the limits of stitch widths which are generally employed in sewing of buttonhole side and end borders. The adjustment of these stitch widths is, as specifically illustrated in connection with the embodiment of Figs. 1 to 3, limited by an arcuate recess 43' formed on that edge of the adjusting slider 43 adjacent and facing the gripping member 43' of the adjusting lever 48. Should the adjusting lever 48, therefore, be moved beyond one or the other end of the recess 43', tending to increase or decrease the stitch width still more, the termini of the arcuate end portions 51 or 51" of the cam slot '1 come into engagement with the pivot pin 49 of the adjusting lever 48 and inhibit a further swinging of the eccentric carrier 46. The oblique cam slot 51 could, of course, be completely straight, rather than as shown, without its function being varied in any manner.

In lieu of providing the cam slot 51 in the eccentric carrier 46 for movement past the pivot pin 49 of the adjusting lever 48, it would be possible to form the cam slot in the housing bottom plate 20 and to provide on the eccentric carrier 46 a guide pin extending into and riding along this slot.

By way of rsum, therefore, it will be seen that the present invention basically provides means which, during the longitudinal displacement of the eccentric carrier, positively impart to the latter a concurrent angular or swinging displacement about the extension of the eccentric, this extension at the same time being the means providing the pivot axis for the cloth-displacing lever and being shifted longitudinally of the lever and the housing to vary the length of the front (left-hand) lever arm of the cloth-displacing lever so as to vary the throw of the latter and the cloth-displacing foot.

Various changes and modifications may be made withoutdeparting from the spirit and scope of the present invention and it is intended that such obvious changes and modifications be embraced by the annexed claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent, is:

1. In a zig-zag stitch attachment for use in connection with a needle-equipped sewing machine; a drive housing, cloth-displacing means including a lever extending substantially longitudinally of said housing and a cloth-displacing foot carried by said lever at one of the ends thereof, drive means located in said housing and operatively connected to said lever adjacent the other end thereof for imparting to said lever reciprocal swinging movements about a predetermined pivot axis intermediate said ends and in a direction transverse to the direction of sewing, said drive means being constructed for actuation in response to operation of said needle during sewing, eccentric means engaging said lever intermediate said ends thereof for sliding movement longitudinally therealong and including extension means defining said pivot axis and guided by said housing for sliding movement longitudinally of the latter, carrier means rigidly connected to said eccentric means, and means operatively connected to said carrier means for concurrently displacing the same longitudinally of said housing and angularly about said pivot axis, whereby the longitudinal displacement of said carrier means moves said eccentric means with said extension means along said lever to shift said pivot axis longitudinally of said lever and to thereby vary the extent of said swinging movement of said lever and foot, while the concurrent angular displacement of said carrier means rotates said eccentric means and thereby laterally shifts the median line of the zigzag stitches of said needle in cloth disposed beneath said foot.

2. In an attachment according to claim 1; said means for angularly displacing said carrier means comprising guide pin means and cam means in sliding engagement with one another, one of said guide pin means and cam means being disposed on said housing and the other being disposed on said carrier means.

3. In an attachment according to claim 2; an adjusting lever operatively connected to said carrier means and constituting the means for longitudinally displacing the same, said guide pin means comprising a pin fixed to said housing and pivotally carrying said adjusting lever, said cam means comprising a cam slot provided in said carrier means, and said pin extending through said cam slot.

4. In an attachment according to claim 3; said cam slot being oriented substantially obliquely to the longitudinal dimension of said housing.

5. In an attachment according to claim 3; a coupling element articulated at one portion to said eccentric means and at another portion to said adjusting lever and thus providing the operative connection between said adjusting lever and said carrier means.

6. In an attachment according to claim 3; said adjusting lever being articulated directly to said carrier means and being provided with an elongated guide slot arranged to permit a relative motion between said adjusting lever and said carrier means in accordance with the characteristics of said cam slot.

7. In an attachment according to claim 6; said guide slot surrounding and slidably accommodating said pin pivotally carrying said adjusting lever.

8. In an attachment according to claim 6; a link bolt connected to both said adjusting lever and said carrier means and establishing the articulation therebetween, said guide slot in said adjusting lever surrounding and slidably accommodating said link bolt.

9. In an attachment according to claim 1; said carrier means comprising a coupling element constructed in the form of a crank connecting rod, said means for longitudinally and angularly displacing said carrier means comprising an adjusting lever swingably supported by said housing, said coupling element being articulated at one portion to said adjusting lever and connected at another portion to said eccentric means, said extension means guiding said other portion of said coupling element for movement longitudinally of said housing.

10. In an attachment according to claim 1; means for adjusting said eccentric means on said carrier means in a direction transverse to the longitudinal dimension of said carrier means.

11. In an attachment according to claim 10; said adjusting means comprising a transverse slot provided in said carrier means, a bolt extending from said eccentric means and through said transverse slot, and clamping means for clamping said bolt to said carrier means and in position in said slot.

12. In an attachment according to claim 10; said means for longitudinally and angularly displacing said carrier means comprising an adjusting lever operatively connected to said carrier means, a pivot pin afiixed to said housing and pivotally supporting said adjusting lever, said carrier means being provided with a cam slot having a central portion oriented substantially obliquely to the longitudinal dimension of said housing and further having oppositely curved end portions, said pivot pin extending through said cam slot, whereby angular displacement of said carrier means is possible when said pin extends through said central portion of said cam slot, and impossible when said pin extends through either of said end portions of said cam slot.

13. In a zig-zag stitch attachment for use in connection with a sewing machine having a presser bar, a vertically reciprocal needle bar, and a needle carried by the latter; a longitudinally slotted drive housing adapted to be fixedly supported by said presser bar, a longitudinally slotted cloth-displacing lever extending substantially longitudinally of said housing, a cloth-displacing foot carried by said lever at one of the ends thereof, drive means located in said housing and operatively connected to said cloth-displacing lever at the other end thereof for imparting to said lever reciprocal swinging movement about a predetermined pivot axis intermediate said ends and in cloth-displacing lever intermediate said ends thereof and 7 including a guide projection defining said pivot axis and riding in the slot in said housing for sliding movement longitudinally of the latter, an eccentric carrier rigidly connected to said eccentric bolt, and an adjusting lever pivotally supported by said housing and operatively connected to said carrier for displacing that portion of the same connected to said eccentric bolt longitudinally of said housing and for concurrently therewith displacing said carrier angularly about said pivot axis, whereby the longitudinal displacement of said carrier portion moves said eccentric bolt with said guide projection along said slots to shift said pivot axis and thus vary the extent of said swinging movement of said cloth-displacing lever and foot, while the concurrent angular displacement of said carrier rotates said eccentric bolt about said pivot axis to laterally shift the stitching region of said needle in cloth disposed beneath said foot.

14. In a zig-zag stitch attachment designed for use in connection with a needle-equipped sewing machine and having a drive housing, a cloth-displacing lever swingably supported by said housing, drive means located in said housing and operatively connected to said cloth-displacing lever at one end thereof for imparting to said lever reciprocal swinging movements about a predetermined pivot axis intermediate the ends of said cloth-displacing lever and in a direction transverse to the direction of sewing in response to reciprocal sewing movements of said needle, eccentric means slidably engaging said cloth-displacing lever intermediate said ends thereof, said eccentric means including extension means defining said pivot axis and guided by said housing for sliding movement longitudinally of the latter, and a carrier for said eccentric means fixedly connected to the latter and arranged for longitudinal displacement along said housing for shifting the location of said pivot axis so as to vary the throw of said cloth-displacing lever, and for swinging displacement for shifting laterally with respect to-said needle the stitching region of cloth being sewed; the improvement comprising means operatively connected to said carrier for displacing the same longitudinally of said housing and for concurrently therewith positively imparting to said carrier a swinging displacement about said pivot axis.

References Cited in the file of this patent UNITED STATES PATENTS Enos Apr. 16, 1957 

